/*
 * Copyright 2008 Zoundry LLC, Inc.  All Rights Reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 */
package org.zoundry.gaedt.core.util;

import java.io.StringReader;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.w3c.dom.Document;
import org.xml.sax.InputSource;
import org.zoundry.gaedt.core.ZGaeException;


/**
 * A generic XML parser.
 */
public class ZGaeXmlParser
{
    /** The singleton parser instance. */
    private static final ZGaeXmlParser sInstance = new ZGaeXmlParser();

    /**
     * Gets the xml parser instance.
     */
    public static final ZGaeXmlParser getInstance()
    {
        return sInstance;
    }

    /**
     * C'tor.
     */
    private ZGaeXmlParser()
    {
    }

    /**
     * Parse the into an XML document.
     *
     * @throws ZGaeException
     */
    public Document parse(String aXmlString) throws ZGaeException
    {
        InputSource inputSource = new InputSource(new StringReader(aXmlString));
        inputSource.setSystemId("urn:" + aXmlString.hashCode());
        return parse(inputSource);
    }

    /**
     * Parse the input source into an XML document.
     *
     * @param aInputSource
     */
    public Document parse(InputSource aInputSource) throws ZGaeException
    {
        Document document = null;
        try
        {
           DocumentBuilder db = createDocumentBuilder();
           document = db.parse(aInputSource);
        }
        catch(Exception e)
        {
            throw new ZGaeException(e);
        }

        return document;
    }

    /**
     * Creates a new document builder.
     *
     * @throws ParserConfigurationException
     */
    private DocumentBuilder createDocumentBuilder() throws ParserConfigurationException
    {
        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        factory.setNamespaceAware(true);
        factory.setValidating(false);
        return factory.newDocumentBuilder();
    }
}
